---
title: backgroundSystem
framework: sensorkit
role: symbol
role_heading: Type Property
path: sensorkit/srphotoplethysmogramsample/usage-swift.struct/backgroundsystem
---

# backgroundSystem

A reading taken by the system in the background.

## Declaration

```swift
static let backgroundSystem: SRPhotoplethysmogramSample.Usage
```

## Discussion

Discussion The system takes this reading while performing various heart features on watchOS — such as background blood oxygen, atrial fibrillation (AFib), and low-cardio notifications.

## See Also

### Getting the reading method

- [foregroundHeartRate](sensorkit/srphotoplethysmogramsample/usage-swift.struct/foregroundheartrate.md)
- [deepBreathing](sensorkit/srphotoplethysmogramsample/usage-swift.struct/deepbreathing.md)
- [foregroundBloodOxygen](sensorkit/srphotoplethysmogramsample/usage-swift.struct/foregroundbloodoxygen.md)